The invention relates to cooling devices in aircraft. In particular, the invention relates to a cooling system for an aircraft, an aircraft comprising such a cooling system, the use of a cooling system in an aircraft, and a method for cooling a medium in an aircraft.
In the technical field of aircraft construction and aeronautical engineering generally, for the purpose of reducing aerodynamic drag during flight, removal by suction of the so-called boundary layer, i.e. the air layer that flows directly along the aerodynamic surface areas of the aircraft, can take place. This measure is based on the laws of aerodynamics, which laws state that the aerodynamic drag of laminar boundary layer flows is significantly less than that of turbulent boundary layer flows. It is therefore possible to reduce aerodynamic drag of an aircraft during cruising in that at least some of the boundary layer flow on wing surfaces and tail unit surfaces is kept so as to be laminar. The air stream removed by suction from the boundary layer can be of a magnitude of several kilograms per second, depending on which surfaces and how many surfaces have been selected.
It has been shown that generating laminar flow may result in a significant reduction in an aircraft's air drag, and may thus result in fuel savings.
Cooling in an aircraft presently takes place predominantly by admitting outside air by way of a ram air channel, in particular for cooling the air conditioning unit. However, as a result of their openings, ram air channels may create additional air drag on the aircraft, which air drag may have a negative effect on the overall performance of the aircraft as far as fuel consumption and flight speed are concerned.
Due to the use of further electrical systems in future aircraft, it may be assumed that the required cooling output will increase. However, the cooling output provided by ram air cannot be increased indefinitely because of the resulting additional air drag.